You got me to thinking about the 7/9 cars. I know the code is the same and VSS performs the same function in the 940 with Bosch (LH2.4) but I don't recall anyone ever having a Regina idle problem like that.

So, I got to playing with VADIS, switching between Regina and LH2.4 on a "94 940" and sure enough, the DTC is there, with all the same troubleshooting information except the reference to idle symptoms in the case of Regina.

I'm still unclear why Bosch does it. I might speculate, but I'd rather not, just to keep the confusion level down in this thread. The symptom in every case has been high idle at stoplights and such which reverts to normal on shutdown and restart. It doesn't happen in the driveway, because the ECU must wait for load to occur.

It has plagued those of us who come to the board and want to know what their broken speedometer, removed cluster, or busted differential sensor wire has to do with idling. The 311 gives it away. Here's what Volvo says about both the Bendix and Bosch fuel controllers, so I assume it was specified to the supplier:

"If the engine speed (RPM) is above 2100 rpm, the load signal is in the part-load range and the control module does not receive a signal from the speedometer for 8 seconds a diagnostic trouble code (DTC) is stored."
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Art Benstein near Baltimore

Always keep your words soft and sweet, just in case you have to eat them.